An Asymmetry in the IOD and ENSO teleconnection pathway and its impact on australian climate
Article
Article Title | An Asymmetry in the IOD and ENSO teleconnection pathway and its impact on australian climate |
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ERA Journal ID | 1978 |
Article Category | Article |
Authors | Cai, Wenju, van Rensch, Peter, Cowan, Tim and Hendon, Harry H. |
Journal Title | Journal of Climate |
Journal Citation | 25 (18), pp. 6318-6329 |
Number of Pages | 12 |
Year | 2012 |
Publisher | American Meteorological Society |
Place of Publication | United States |
ISSN | 0894-8755 |
1520-0442 | |
Digital Object Identifier (DOI) | https://doi.org/10.1175/JCLI-D-11-00501.1 |
Web Address (URL) | https://journals.ametsoc.org/view/journals/clim/25/18/jcli-d-11-00501.1.xml |
Abstract | Recent research has shown that the climatic impact from El Niño–Southern Oscillation (ENSO) on middle latitudes west of the western Pacific (e.g., southeast Australia) during austral spring (September–November) is conducted via the tropical Indian Ocean (TIO). However, it is not clear whether this impact pathway is symmetric about the positive and negative phases of ENSO and the Indian Ocean dipole (IOD). It is shown that a strong asymmetry does exist. For ENSO, only the impact from El Niño is conducted through the TIO pathway; the impact from La Niña is delivered through the Pacific–South America pattern. For the IOD, a greater convection anomaly and wave train response occurs during positive IOD (pIOD) events than during negative IOD (nIOD) events. This “impact asymmetry” is consistent with the positive skewness of the IOD, principally due to a negative skewness of sea surface temperature (SST) anomalies in the east IOD (IODE) pole. In the IODE region, convection anomalies are more sensitive to a per unit change of cold SST anomalies than to the same unit change of warm SST anomalies. This study shows that the IOD skewness occurs despite the greater damping, rather than due to a breakdown of this damping as suggested by previous studies. This IOD impact asymmetry provides an explanation for much of the reduction in spring rainfall over southeast Australia during the 2000s. Key to this rainfall reduction is the increased occurrences of pIOD events, more so than the lack of nIOD events. |
ANZSRC Field of Research 2020 | 370105. Atmospheric dynamics |
370202. Climatology | |
370109. Tropospheric and stratospheric physics | |
Public Notes | File reproduced in accordance with the copyright policy of the publisher/author. |
Byline Affiliations | Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia |
Australian Bureau of Meteorology |
https://research.usq.edu.au/item/z09wz/an-asymmetry-in-the-iod-and-enso-teleconnection-pathway-and-its-impact-on-australian-climate
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